Phenols in Quality Olive Oil Suppress Breast Cancer Gene

WEDNESDAY Dec. 17, 2008 -- Spanish researchers have identified anti-cancer chemicals in extra-virgin olive oil that may help explain the apparent link between eating an olive oil-rich Mediterranean diet and a reduced risk of breast cancer.

Extra-virgin olive oil, which is produced by pressing olives without the use of heat or chemical treatments, contains phytochemicals that are otherwise lost in the refining process. The Spanish researchers separated extra-virgin olive oil into fractions and tested these against breast cancer cells in the lab. They found that all the fractions that contained major extra-virgin phytochemical polyphenols (lignans and secoiridoids) effectively inhibited the breast cancer gene HER2.

The study was published in current issue of BMC Cancer.

"Our findings reveal for the first time that all major complex phenols present in extra-virgin olive oil drastically suppress overexpression of the cancer gene HER2 in human breast cancer cells," Javier Menendez, of the Catalan Institute of Oncology, said in a BioMed Central news release.

While the study results offer new insights into how extra-virgin olive oil may help reduce HER2 breast cancer risk, the findings must be viewed with caution.

"The active phytochemicals [i.e. lignans and secoiridoids] exhibited tumoricidal effects against cultured breast cancer cells at concentrations that are unlikely to be achieved in real life by consuming olive oil," the researchers noted.

However, they also said their findings, "together with the fact that humans have safely been ingesting significant amounts of lignans and secoiridoids as long as they have been consuming olives and extra-virgin oil, strongly suggest that these polyphenols might provide an excellent and safe platform for the design of new anti-breast cancer drugs."